Use refactored remapping schemes

[iangrooms]

There are new recommended re-factorings of several remapping schemes, including PPM_CW which is our current default. We should update to

REMAPPING_SCHEME = C_PPM_CW
VELOCITY_REMAPPING_SCHEME = C_PPM_CW

[alperaltuntas]

I am re-opening this issue because refactor still needs some adjustments, I believe.

Firstly, there’s an if statement that appears in several Recon1d_ modules:

if ( ( u2 - u1 ) * ( u1 - u0 ) <- 0.0 )

I believe the intended condition was:

if ( ( u2 - u1 ) * ( u1 - u0 ) <= 0.0 )

Additionally, and more critically, we’re seeing NaN values for u2 in the C_PPM_CW case:

  do K = 2, n ! K=2 is interface between cells 1 and 2
    ...
    u2 = u(k+1)

when k = n. This is likely due to an off-by-one access error.

Since switching from PPM_CW to C_PPM_CW isn’t critical for the next beta tag, I’ve reverted that change in #298. Once these issues are verified and resolved, we can reintroduce the update safely.

Mentioning @adcroft

[adcroft]

That <- is indeed a typo. @marshallward pointed this out to me a while before the shutdown. I've just checked that changing to "<=" makes no difference to the tests, but I have not yet done a regression test with OM4. I think it will pass.